Tracked vehicles are commonly used as a platform for specialized equipment and for transport of personnel over rough, soft, or snowy terrain where wheeled vehicles cannot function. Such vehicles include pavers, harvesters, military vehicles, and earthmovers. A typical tracked vehicle includes a two track assemblies, one located on each lateral side of the vehicle. Each track assembly includes a single continuous track, mounted about driven by a drive wheel engaged to the inner surface of the track, and a plurality of road wheels and idlers. The drive wheels are powered by an internal combustion engine or electric motor housed within the hull of vehicle and connected to the drive wheel via a transmission. The drive wheels and other wheels are attached to the body by a variety of axle and suspension assemblies. Hydraulic fluid lines pass from the body into the track assemblies to power brakes engaged to the road wheels.
Conventional tracked vehicles, with a single continuous track assembly on each side, have a number of drawbacks. If one track assembly is incapacitated, the vehicle cannot be driven until the track assembly is disassembled, the problem is diagnosed, and a repair is made. This can be inconvenient or impossible when the vehicle is at a great distance from a repair shop and maintenance personnel, and hazardous to the vehicle crew when the track is damaged in an inclement or hostile environment. The repair of conventional tracked vehicles also poses costly logistical problems. Trained technicians skilled in diagnosing and repairing track assemblies must accompany the tracked vehicle or be kept within rapid travel distance. A large array of spare parts must maintained and kept available for rapid shipping. When the vehicle is in a remote location, shipping is can be difficult or impossible.
When a conventional tracked vehicle suffers the incapacitation of a track assembly in a remote or hostile location, the crew of the vehicle may be endangered. They may be stranded until a repair crew and parts arrive. Even if the crew is able to leave the vehicle and make repairs, they may be endangered by exposure to harsh climate or other environmental hazards.
Conventional tracked vehicles also have shortcomings in terms of hull configuration and space and weight distribution. The hull bottoms are riddled with gaps and projections to accommodate the axles, suspension assemblies, transmissions, and hydraulic lines required to connect the track assemblies to the hull and to an engine housed within the hull. The complex and partially open structure of the hull bottom renders the vehicle vulnerable to water infiltration, snagging on projecting terrain features, and upward-directed explosive forces. Furthermore, space that could be occupied by crew is instead consumed by the engine and transmission components.
There is a need for a tracked vehicle with track assemblies that can be readily removed and replaced as a unit, by unskilled crew. There is a need for a tracked vehicle which can suffer the loss of a track assembly and continue to locomote. There is a need for a tracked vehicle wherein the elements of a motor and suspension are contained within the track assemblies and not within the hull of the vehicle.